1. Technical Field
The present invention relates to a robot control device, a robot, and a robot control method.
2. Related Art
In the related art, a robot with a robot arm is known. The robot arm is configured when a plurality of links are connected to each other via joint portions, and an end effector, for example, a hand is mounted on a link closest to a distal end. The joint portions are driven by a motor, and the joint portions are driven to turn the links. During the operation of the robot, an encoder detects a rotational angle of the motor, and the detected rotational angle is used to control the robot.
However, there is a problem in that a torque transmission mechanism, a speed reducer, and the links connected to the motor are not rigid bodies but have elasticity, thereby causing the robot arm to vibrate during the operation of the robot.
In a method that is devised so as to solve the problem, the vibration of a distal end portion of the robot arm is prevented by attaching an inertia sensor to the distal end portion of the robot arm, detecting the acceleration of the distal end portion of the robot arm using the inertia sensor, and executing a control via distribution of respective correction values to motors for turning the links using a Jacobi matrix or the like, the correction values being intended to prevent the vibration of the distal end portion of the robot arm (for example, JP-A-2011-136395).
However, in this method, when the posture of the robot arm is close to a specific posture, that is, when the robot arm is used in a stretched posture, the distribution of the respective correction values to the motors increases, that is, a feedback amount considerably increases in each of the motors, and thus the control of the robot becomes unstable.